Bridge



(No Model.)

Patented Aug. 20, 1895.

TE? 5 (fi/ 1 I UNITED STATES PATENT OFFICE.

ROBERT P. LAMONT, OF CHICAGO, ILLINOIS.

BRIDGE.

SPECIFICATION forming part of Letters Patent No. 544,733, dated August20, 1895.

Application filed January 5, 1895.

T0 CLZZ whom it may concern-.-

Be it known that 1, ROBERT P. LAMONT, a citizen of the United States,residing at Chicago, county of Cook, State of Illinois, have invented acertain new and useful Improvement in Bridges; and I declare thefollowing to be a full, clear, and exact description of the invention,such as will enable others skilled in the art to which it pertains tomake and use the same, reference being had to the accompanying drawings,which form a part of this specification.

.One of the principal objections heretofore raised to that class ofbridge known as the Bascule bridge, as well as to other forms of tiltingbridges, has been in the fact that that portion of the bridge which isdepressed must be of comparatively great length in order to increase theleverage sufficient to permit the anchorage to sustain and hold theouter or elevated end when heavily loaded,as is often the case. In longspans, particularly where the leverage length of the span or outerportion is great, the inner or depressed end is of necessity made solong that it is difiicult to provide a way or space into which it can bedepressed, often necessitating a very deep excavation, thus materiallyincreasing the cost and time of construction. Again, in this type oftilting bridges it has heretofore been customary to provide bothportions of the bridgesthat is, both the portion that is elevated andthe portion that is depressed-with flooring, and thus make both portionsa part of the roadway when the bridge is closed or in its normalposition; but the great objection to this is that when the bridge isopened a space normally filled by the depressible end is left betweenthe stationary flooring and the elevated portion.

My invention has two objects, first, to so locate the anchorage for thedepressed end that the latter may, in proportion to the outer or spanend, be materially shortened, thus practically obviating the necessityof deep excavations, and, second, to obviate the objectionable spaceabove referred to. These objects I accomplish by a combination ofdevices hereinafter described and claimed.

Figure 1 is a side elevation; Fig. 2, a plan view of a bridge embodyingmy invention.

In carrying out my invention, A represents Serial No, 533,901. (Nomodel.)

the abutment or pier on which the bridge is supported and pivoted, and Athe supportingposts extending upward therefrom and to which thebridge-section is directly pivoted. In the above drawings I have shownbut a single section. Obviously there might or might not be acorresponding section on the opposite side of the space to be bridged.

B represents the bridge proper, pivoted at b to the posts A.

The particular construction of the framework of the bridge isimmaterial, and I have herein shown only sufficient to illustrate thecarrying out of my invention.

13' B are the main side girders of the bridge, connected together at theinner or depressed end I) by the cross-beam B C represents the masonryconstituting the anchorage of the end b. v

D are beams substantially on a level with the bridge when in its normalposition, and E are. tie-rods connecting the ends of the beams D withthe anchorage C. The opposite ends of the beams D are engaged to theabutment A. It will be observed that the anchored ends of the beams Dare a considerable distance back from the ends 1) of the bridge and arelocated above the cross-beam B, which, when the bridge reaches ahorizontal position, comes into contact with the beams D and forms astop to prevent the further elevation of the end 6 and consequently thedepression of the end 19 The advantage of this feature of my inventionwill now be apparent. The shortening of the end I) to the proportionsshown herein would be practically impossible if the anchorage wasdirectly under the end of the portion Z), since while the anchoragemight be sufficient while there was no load on the outer end 11 yet whenheavily loaded, as is often the case, the leverage would be so great onthe anchorage as to make it liable to give, as well as an enormousstrain on the pivot and other parts. By moving this anchorage back,however, and causing the end b of the bridge to bear on the beams D, theleverage length of the portion Z) when horizontal is practically fromthe pivotal point I) to the tie-rods E instead of from the pivotal pointI) to the end of the portion b, as would be the case if the beams D werenot provided. As above explained, the por- ICO tion Z) can thus bematerially shortened, deep excavations are obviated, and an extremelysimple yet strong trusswork is obtained.

, I will now describe the second feature of my invention.

F represents the flooring of the bridge proper that is, the movableportion or tilting section, and F the flooring of the approach. It willbe observed that the rear or depressible end I) of the bridge is notfloored, but that the flooring F of the approach extends to a pointbeyond the vertical plane of the pivotal point of the bridge andterminates at G. The flooring of the bridge proper begins at this point,so that when the bridge is closed there is a continuous roadway. \Vhenthe bridge is opened, as shown by dotted lines, Fig. 1, the endfof theflooring on the bridge describes a semicircle and comes to a pointclosely adjacent to the stationary-approach flooring, as at f, thusforming an effectual bridge-guard and yet leaving an unbroken surface upto the pier.

\Vhat I claim is 1. In a tilting bridge the combination with the inneror depressible end of the anchorage for the same located out of the samevertical plane with said end, and one or more beams or levers engaged tothe anchorage against which the said bridge end may bear, substantiallyas described.

2. In a tilting bridge the combination with the bridge abutment on whichthe bridge is pivoted, and the inner or depressible end of the bridge,of the anchorage located out of the vertical plane of the said end,.andlevers or beams engaged to the anchorage and to the abutment, and stopson the said bridge adapted to engage said beams, substantially asdescribed.

3. In a tilting bridge the combination with the bridge section and itsflooring, of the approach and its fiooringthe latter extending above andbeyond the pivot on which the bridge tilts, substantially as described.

In testimony whereof I sign this specification in the presence of twowitnesses.

ROBERT P. LAMONT. Witnesses:

XV. H. CHAMBERLIN, FLORENCE KING.

